How can I have my command-line arguments parsed automagically using annotations?

Question

I'd like something like the following to work:

public class A {
    @command_line_arg{"argname1"}
    static boolean x;

    @command_line_arg{"argname2"}
    static List<String> y;

    void main(String[] args) {
        /* perhaps a call such as parseArgs(); here */
        System.out.println("got argname1 = " + x);
        System.out.println("got argname2 = " + y);
    }
}

What library do I need to use?

(somewhat related to this.)

score 2 · Accepted Answer · edited May 23 '17 at 11:48

(based on @fge's answer.)

One can use JCommander with statics:

public class A {

    @Parameter(names = "-argname1")
    static boolean x;
    @Parameter(names = "-argname2", variableArity = true)
    static List<String> y;

    @Parameter
    public static List<String> remainingParameters;

    void main(String[] args) {
        new JCommander(A.class.newInstance(), args);
        System.out.println("got argname1 = " + x);
        System.out.println("got argname2 = " + y);
    }
}

score 1 · Answer 2 · edited Feb 04 '13 at 08:09

1

You can try klab-commons-cli, it adds annotations to Apache commons-cli; there is no distribution jar, you just use the source code. An alternative, which doesn't leverage commons-cli, but provides a distribution library, is args4j.

edited Feb 04 '13 at 08:09

einpoklum

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answered Feb 03 '13 at 11:13

remigio

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The downloads section there seems to be empty. Do I have to use the sources? – einpoklum Feb 03 '13 at 15:22
I've edited my answer, if you need a jar there is an alternative, it doesn't leverage commons-cli, however it's as valid as the other one. – remigio Feb 04 '13 at 07:46
What are the pros and cons of the first over the second? – einpoklum Feb 04 '13 at 08:06
The first is a layer over Apache commons-cli, a commonly used and appreciated library, anyway both are valid solutions. – remigio Feb 04 '13 at 08:51

score 1 · Answer 3 · answered Feb 03 '13 at 17:01

1

JCommander may be of some use to you. It uses annotations to describe all command line arguments and generates options/help text for you.

Quoting the example found on the web site:

public class JCommanderExample {
  @Parameter
  private List<String> parameters = new ArrayList<String>();

  @Parameter(names = { "-log", "-verbose" }, description = "Level of verbosity")
  private Integer verbose = 1;

  @Parameter(names = "-groups", description = "Comma-separated list of group names to be run")
  private String groups;

  @Parameter(names = "-debug", description = "Debug mode")
  private boolean debug = false;
}

answered Feb 03 '13 at 17:01

fge

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And will this work with static variables as well? I only need to run the main method in my app class... – einpoklum Feb 03 '13 at 17:10
Not that I know of... But you can just do `new Main()` in your `main()` method and run it. You will only have one instance at run time, so that's no big deal. – fge Feb 03 '13 at 17:44

How can I have my command-line arguments parsed automagically using annotations?

3 Answers3